Publishers
- Clymer 3
- CMG Publishing 5
- Co-Operative Printing Sociaty Limited 1
- Co-operative Wholesale Society 2
- Cobden-Sanderson 1
- Cobham Plc 1
- Cocorico 1
- Colin A Pomeroy 1
- Colin Baxter Photography Ltd. 1
- Colin Buchanan And Partners 1
- Colin Orchard 1
- Collection Parthenope 1
- Collectors' Books 1
- College St. Centenary Committee 1
- Collet's 1
- Collier Macmillan Publishers 2
- Collins 480
- Collins & Harvill 2
- Collins and Harvill 1
- Collins Clear-Type Press 94
- Collins Colour Camera Books 1
- Collins Lions 2
- Collins Voyager 1
- Collins Willow 3
- Colmans Foods 1
- Colnaghi And Co. 1
- Colnet 2
- Colorado Railroad Museum 1
- Colorgravure 1
- Colour Library Books 2
- Colour Library Direct 2
- Colourbox Publishing 1
- Colourpoint 2
- Columbia University Press 5
- Combined Publishing 2
- Commission Of Conservation Canada 1
- Commonwealth Agricultural Bureaux 1
- Commonwealth Scientific And Industrial Research Organization 1
- Commonwealth War Graves Commission 2
- Company Of Stationers 1
- Compassverlag 1
- Compendium 1
- Comstock Publishing Associates 2
- Comstock Publishing Company Inc. 1
- Concord Publications Co. 1
- Connaissance Du Rail 4
- Consejo Superior De Investigaciones Cintificas 1
- Conservation Press 1
- Consiglio Nazionale Delle Ricerche 1
- Constable 14
- Constable & Co. Ltd. 21
- Constable and Company Ltd. 20
- Constable Young Books 3
- Constable Young Books Ltd. 1
- Contact Publications Limited 1
- Continuum 1
- Conway 2
- Conway Maritime Press 17
- Copernic 2
- Copernicus 1
- Coppenrath 1
- Copple House Books 1
- Corgi 1
- Corgi Yearling Books 1
- Cornell University Press 4
- Cornish Brothers Limited 4
- Cornmarket 1
- Cornstalk Publishing 1
- Cornstalk Publishing Company 1
- Corris Railway Society 1
- Costello 1
- Cote D'Or 1
- Coterie Press Limited 5
- Council Of Museums In Wales 1
- Country & Sporting Publications 1
- Country Life 22
- Country Life Books 1
- Country Life Limited 17
- Country Life Ltd. 11
- Countryside Books 7
- Courage Books 1
- Coventry University Enterprises Ltd. 1
- Coward-McCann Inc. 1
- CP Press 2
- Crash Media Group 1
- CRC Press 7
- Crecy 2
- Crecy Books 2
- Crecy Publishing Limited 5
- Crescent Books 2
- Cricket Books 1
- Croil 1
- Croner Publications 1
- Croom Helm 8
- Croom Helm Ltd. 1
- Crosby Lockwood 1
- Crosby Lockwood and Son 3
- Crown Publishers 1
- Crown Publishers Inc. 1
- Crowood 3